CN111173799A

CN111173799A - Balance valve, hydraulic cylinder control system, crane and lowering servo control method of crane

Info

Publication number: CN111173799A
Application number: CN201911395626.6A
Authority: CN
Inventors: 苏洪昌; 杨红; 胡娟; 林伟; 夏丹枫
Original assignee: Changde Zhonglian Zhongke Hydraulic Co ltd
Current assignee: Changde Zhonglian Zhongke Hydraulic Co ltd
Priority date: 2019-12-30
Filing date: 2019-12-30
Publication date: 2020-05-19

Abstract

The invention relates to a balance valve, which comprises a servo actuator valve rod (5) and a gain adjustment control piston (1c), wherein a first hydraulic acting surface (S1) is formed on the servo actuator valve rod at an opening and closing flow passage opening part (S3) to bear axial hydraulic acting force towards a main spring cavity (6), and the servo actuator valve rod is also provided with a second hydraulic acting surface (S2) exposed to a second oil cavity (8) or an oil cavity communicated with the second oil cavity to bear axial hydraulic acting force towards a piston cavity (12), wherein the axial effective pressure bearing areas (S1a, S2a) of the first hydraulic acting surface (S1) and the second hydraulic acting surface (S2) are equal. In addition, the invention also discloses a hydraulic cylinder control system, a crane and a lowering servo control method thereof. The invention adopts a special valve core structure and a control mode, so that the balance valve can realize servo control adjustment according to a control signal, the uniformity of the amplitude-variable lowering speed of the crane is improved, and the controllability of the amplitude-variable lowering is improved.

Description

Balance valve, hydraulic cylinder control system, crane and lowering servo control method of crane

Technical Field

The invention relates to a hydraulic valve, in particular to a hydraulically-controlled servo type balance valve. In addition, the invention also relates to a hydraulic cylinder control system and a crane. Further, the invention relates to a crane dead weight lowering servo control method.

Background

With the rapid development of engineering machinery, when a user operates the engineering machinery (such as a crane) for operation, the requirements on the working stability and controllability of the engineering machinery are higher and higher. The engineering mechanical equipment generally adopts a balance valve to realize the stability of the action of a working mechanism, but the problem of non-ideal use effect generally exists in the use of actual working conditions. For example, when the crane performs reverse amplitude operation, the balance valve is lowered by self weight in a hydraulic system of the crane, the load (pressure of a rodless cavity) is gradually increased along with the reduction of the reverse amplitude angle, the amplitude speed is gradually increased, and the lowering uniformity and the inching performance are poor.

In general, conventional balancing valves typically employ a hydraulic connection of a sequence valve in parallel with a check valve, wherein a forward port of the check valve communicates with an output port of the sequence valve and a reverse port of the check valve communicates with an input port of the sequence valve. The balance valve used in engineering machinery is generally specially designed for a sealing structure, a damping structure and the like so as to enhance the stability of the action of a working mechanism.

Chinese utility model patent CN203856793U discloses a balance valve, see fig. 1, when changing width of cloth and descending, control piston 6 moves to main spring chamber 3 direction under the oil pressure effect of control port X department, can promote vice case 8 also to main spring chamber 3 direction slip, make the sealing contact between vice case 8 and main valve core 7 opened, and simultaneously, the throttle groove on vice case 8 is sealed by main valve core 7, the hydraulic oil in the main spring chamber 3 flows to a mouth (oil pocket 2) through the inside oil duct 20 that forms on vice case 8, thereby make the interior oil pressure of main spring chamber 3 reduce, main valve core 7 slides to main spring chamber 3 direction, at this moment, the hydraulic oil in the rodless chamber through B mouth (oil pocket 4) flows along the opposite direction of main and vice case motion, flow to a mouth (oil pocket 2) through throttle groove 13', rodless chamber fluid flows back to the oil tank through a mouth.

These existing balance valves adopt a main valve core and an auxiliary valve core structure, both the piston side and the valve core side are provided with springs, and conical surface sharp corners are adopted for sealing between the main valve core and the auxiliary valve core and between the main valve core and the valve sleeve, so that the sealing structure is complex, and the shape of the throttling groove on the main valve core is also complex, which causes difficulty in processing and greatly increases the processing and equipment cost.

Particularly, after an operating system of the engineering mechanical equipment gives a control signal, the auxiliary valve core cannot effectively adjust the position, so that the position of the main valve core cannot be timely adjusted in a follow-up manner, and the control structure has the defect that the retraction speed of the hydraulic cylinder cannot be effectively, stably and accurately controlled finally, for example, the descending speed of a luffing cylinder of a crane cannot be effectively controlled, and when the crane performs luffing operation, the luffing angle of the crane becomes smaller, the load (pressure of a rodless cavity) gradually increases, the luffing speed is gradually increased, and the lowering uniformity and the jogging performance are poor. Although those skilled in the art have been dedicated to improving this technical problem, for example, chinese utility model CN203627327U tries to perfect the damping structure, it is still impossible to solve the above technical problem perfectly.

In view of the above, there is a need to design a balanced valve that overcomes the above technical difficulties and effectively solves or alleviates the above technical drawbacks.

Disclosure of Invention

The basic technical problem to be solved by the invention is to provide a balance valve, which can realize the servo self-adaptive adjustment of a valve rod according to a hydraulic control signal, thereby improving the speed uniformity of a hydraulic working mechanism and improving the control stability.

Further, the technical problem to be solved by the present invention is to provide a hydraulic cylinder control system, wherein a balance valve on a working oil path of the hydraulic cylinder control system can realize servo adaptive adjustment, so that the uniformity of the working speed of the hydraulic cylinder can be improved, and the control stability can be improved.

In addition, the technical problem to be solved by the invention is to provide the crane, the balance valve on the working oil circuit of the luffing hydraulic cylinder control system of the crane can realize the servo self-adaptive adjustment of the valve rod according to the hydraulic control signal, so that the uniformity of the luffing lowering speed of the crane is improved, and the control stability of luffing lowering is improved.

In addition, the invention also aims to solve the technical problem of providing a crane dead weight lowering servo control method which can improve the stability and the speed uniformity of the inverted amplitude operation of the crane.

In order to solve the above technical problem, the present invention provides a balance valve, including a valve body module formed with a first port and a second port, wherein the balance valve further includes: the servo actuating valve rod can be slidably accommodated in the hollow cavity of the valve body module, a main spring cavity located at one axial end of the servo actuating valve rod and a first oil cavity and a second oil cavity which are axially distributed at intervals and respectively formed along the circumferential direction of the servo actuating valve rod are separated from the hollow cavity, the first oil cavity is communicated with the first port, the second oil cavity is communicated with the second port, and a main spring used for applying preset elastic thrust to one axial end of the servo actuating valve rod is arranged in the main spring cavity; and a gain adjustment control piston which is accommodated in a piston chamber at the other axial end of the servo actuator valve rod and can push the servo actuator valve rod to move toward the main spring chamber under the drive of hydraulic control oil introduced from a hydraulic control port of the balance valve, so that the first oil chamber is communicated with the second oil chamber; the servo actuating valve rod is provided with a first hydraulic acting surface at the opening and closing through flow port part corresponding to the first oil cavity and the second oil cavity, and the first hydraulic acting surface can be gradually exposed to bear axial hydraulic acting force towards the main spring cavity in the process that the servo actuating valve rod moves to enable the first oil cavity to be communicated with the second oil cavity; and the servo actuating valve rod is also provided with a second hydraulic acting surface, the second hydraulic acting surface is exposed in the second oil cavity or the oil cavity communicated with the second oil cavity so as to bear the axial hydraulic acting force towards the piston cavity, and the axial effective pressure area of the first hydraulic acting surface is equal to the axial effective pressure area of the second hydraulic acting surface.

Preferably, a load feedback oil cavity is further formed in the valve body module along the circumferential direction of the servo actuator valve rod, the load feedback oil cavity is communicated with the second oil cavity through a load feedback oil passage formed in the valve body module, and the second hydraulic acting surface is exposed to the load feedback oil cavity.

Specifically, the main spring cavity is provided with a spring pressing seat, the main spring is installed between the spring pressing seat and an end cover spring seat, and the main spring applies elastic force to the axial end of the servo actuating valve rod through the spring pressing seat.

Preferably, a through central oil passage is formed at an axial center position of the gain adjustment control piston, the servo actuator valve rod and the spring pressing seat, and each central oil passage is connected with each other to form an oil return passage of the hydraulic oil when the gain adjustment control piston, the servo actuator valve rod and the spring pressing seat are pressed against each other.

Preferably, a partial pressure damping structure is arranged in the central oil passage of the gain adjustment control piston.

Typically, a relief valve is integrated into the valve body module, and an oil inlet of the relief valve is communicated with the first port and an oil outlet of the relief valve is communicated with the second port.

Typically, the valve body module includes a valve block body and a valve sleeve lining the hollow cavity.

Preferably, the gain adjustment control piston divides the piston cavity into a hydraulic control cavity and a movable cavity, the other axial end of the servo actuation valve rod extends into the movable cavity, and the hydraulic control port is communicated with the hydraulic control cavity.

More preferably, an oil inlet damping structure is arranged on a communication oil passage between the hydraulic control port and the hydraulic control cavity.

As a more preferable embodiment, the balance valve further includes a compensation capability control valve disposed on the valve body module, the compensation capability control valve includes a compensation control piston slidably disposed in a compensation piston cavity, the compensation control piston divides the compensation piston cavity into a hydraulic action cavity and a compensation spring cavity, the hydraulic action cavity is communicated with the hydraulic control cavity, a compensation control spring capable of adjusting an elastic force is disposed in the compensation spring cavity, the compensation control spring is preset to apply an elastic force to the compensation control piston, a stop flange is disposed on an outer periphery of the compensation control piston, a circumferential step is disposed on an inner circumferential surface of the compensation piston cavity, and the stop flange and the circumferential step can stop each other when the compensation control piston is moved to a certain position to limit a movement stroke of the compensation control piston.

Further preferably, an axial central oil passage is formed in the compensation control piston, the compensation control spring is sleeved on the spring pushing seat and applies elastic thrust to the end face of the compensation control piston through a forked end of the spring pushing seat, and a sealing ball for plugging a port of the axial central oil passage is arranged between a forked opening of the forked end and the end face of the compensation control piston.

Specifically, the inner diameter of the section of the compensation piston chamber where the circumferential step is provided is larger than the hydraulic-acting chamber and the compensation spring chamber, thereby forming a flange-portion movement chamber of the stopper flange, which communicates with the movable chamber through an oil drain passage.

Typically, the valve body module includes a servo control end cap disposed at one side of the valve block body thereof, and the piston chamber, the pilot port, and the compensation capability control valve are disposed at the servo control end cap.

On the basis of the technical scheme of the balance valve, the invention provides a hydraulic cylinder control system which comprises a hydraulic cylinder, wherein a rod cavity of the hydraulic cylinder is respectively connected with a reversing valve through a first working oil way and a rodless cavity through a second working oil way, the reversing valve is connected with an oil inlet oil way and an oil return oil way, the second working oil way is provided with the balance valve, the balance valve is the balance valve in any technical scheme, a first port of the balance valve is connected with the reversing valve, a second port of the balance valve is connected with the rodless cavity of the hydraulic cylinder, and a hydraulic control port is connected with a hydraulic control oil way.

The invention further provides a crane which comprises a variable amplitude hydraulic cylinder control system, wherein the variable amplitude hydraulic cylinder control system is the hydraulic cylinder control system.

In addition, the invention provides a dead weight lowering servo control method of the crane, which comprises the following steps: firstly, hydraulic control oil is led in through the hydraulic control port to drive the gain adjustment control piston to push the servo actuating valve rod to move, so that the first oil chamber and the second oil chamber are communicated with each other, and the first hydraulic acting surface is gradually exposed to bear hydraulic acting force; secondly, the hydraulic control oil pressure in the hydraulic control cavity is controlled to be in a target control oil pressure range, so that the servo actuating valve rod carries out self-adaptive dynamic position adjustment according to the following formula: x1 × S0-F ═ S1a ×; wherein X1 is the liquid accuse oil pressure in the liquid accuse intracavity, and S0 is the effective pressurized area in the axial of gain adjustment control piston, and F is the main spring is compressed to first oil pocket with the elastic thrust under the second oil pocket intercommunication state each other, and S1a is the effective pressurized area in the axial of first hydraulic pressure working face, and PB is the oil pressure in the second oil pocket, and PB1 is the oil pressure at the switching through-flow mouth position that first oil pocket and second oil pocket communicate each other.

Specifically, in the second step, the pilot oil pressure in the pilot chamber is controlled to be in the target pilot oil pressure range by the external oil pressure regulating device; or the compensation capacity control valve arranged in the balance valve controls the hydraulic control oil pressure in the hydraulic control cavity to be in the target control oil pressure range.

The balance valve adopts a hydraulic control servo control mode, adopts a unique valve core structural form, adopts a servo actuating valve rod with a first hydraulic action surface and a second hydraulic action surface on a valve core, has equal axial effective pressure bearing areas and opposite axial hydraulic action directions on the first hydraulic action surface and the second hydraulic action surface, adjusts a hydraulic control hydraulic value borne by a control piston through a control gain, when the servo actuating valve rod moves to a position enabling the first oil chamber and the second oil chamber to be communicated, the first hydraulic action surface is gradually exposed and bears the hydraulic action force due to the opening of a valve port, at the moment, the servo actuating valve rod carries out self-adaptive dynamic adjustment according to X1 multiplied by S0-F S1a (PB-PB1) by controlling a hydraulic control value signal to a target range, wherein X1 is hydraulic control, S0 is the axial effective pressure bearing area of the gain adjustment control piston, f is the elastic thrust of the main spring of the balance valve when the first oil chamber and the second oil chamber are compressed to be communicated with each other, S1a is the axial effective pressure receiving area of the first hydraulic acting surface, PB is the oil pressure in the second oil chamber, and PB1 is the oil pressure at the opening and closing flow port position where the first oil chamber and the second oil chamber are communicated with each other. Thus, the hydraulic control signal and the load feedback signals PB and PB1 form continuous adjustment to determine continuous self-adaptive servo adjustment of the position of the servo actuating valve rod, and finally ensure that the speed of the hydraulic actuating mechanism tends to a fixed value.

Particularly, when the balance valve is applied to a hydraulic control system of a variable amplitude hydraulic cylinder of an automobile crane and the like, the uniformity of the descending speed of the variable amplitude can be effectively improved, the controllability of the variable amplitude operation is obviously improved, and a servo self-adaptive adjustment relation is formed between a hydraulic control signal and the descending speed of the variable amplitude balance valve in the lowering process, so that the constant speed and the controllability of the variable amplitude are more stable, the variable amplitude operation is more comfortable and safe, the flow compensation and even the overcompensation along with the change of a load when the automobile crane reverses the amplitude is realized, and the stability and the safety of the variable amplitude operation are ensured.

Additional features and advantages of the invention will be set forth in the detailed description which follows.

Drawings

The following drawings are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the scope of the invention. In the drawings:

FIG. 1 is a schematic cross-sectional view of a balanced valve disclosed in prior art CN 203856793U;

FIG. 2 is a schematic cross-sectional view of a balanced valve according to an embodiment of the invention;

FIG. 3 is a schematic cross-sectional view taken along line K1-K1 in FIG. 2;

FIG. 4 is a schematic cross-sectional view of the balancing valve shown in FIG. 2, which indicates hydraulic circuit flow arrows during servo control on the basis of FIG. 2;

FIG. 5 is a schematic cross-sectional view taken along line K2-K2 in FIG. 4;

FIG. 6 is a schematic cross-sectional view of another embodiment of the balancing valve of the present invention, showing another arrangement of the first and second hydraulic actuating surfaces; and

fig. 7 is a block diagram of the steps of the crane dead weight lowering servo control method of the present invention.

Description of the reference numerals of the invention:

1 servo hydraulic control structure unit; 1a, an oil inlet damping structure;

1b a partial pressure damping structure; 1c a gain adjustment piston;

2, a valve body module; 2a valve block body;

2b, a valve housing; 2c servo-controlling the end caps;

3, a main spring; 4, a spring pressing seat;

5 servo actuating the valve stem; 6 a main spring cavity;

7 a first oil chamber; 8 a second oil chamber;

9 load feedback oil chamber; 10a,10b,10c center oil gallery;

11 an overflow valve; 12a piston chamber;

12a liquid control chamber; 12b a movable chamber;

13a compensation capacity control valve; 13a hydraulic action chamber;

13b compensation control piston; 13c compensating spring cavities;

13d sealing rings; 13e axial center oil passage;

13f a sealing ball; 13g compensation control spring

13h circumferential steps; 13i a stop flange;

13j drain oil passage; 13k flange portion motion cavity;

13l of spring pushing seat; a 13m spring adjusting cover;

a a first port; b a second port;

f, compressing the main spring to elastic thrust in a state that the first oil chamber is communicated with the second oil chamber;

ls load feedback oil channel;

oil pressure in the PB second oil chamber;

PB1 oil pressure at the open/close flow port position where the first oil chamber and the second oil chamber are communicated with each other;

s0 is the axial effective pressure area of the gain adjustment control piston;

s1a first hydraulic acting surface; s2 second hydraulic pressure acting surface;

s3 opening and closing flow through port parts of the first oil chamber and the second oil chamber which are communicated with each other;

s1a axial effective pressure area of the first hydraulic action surface;

s2a axial effective pressure receiving area of the second hydraulic pressure acting surface;

an X hydraulic control port; the hydraulic control oil pressure in the X1 hydraulic control cavity;

Detailed Description

The following detailed description of the present invention is provided in conjunction with the accompanying drawings, and it is to be understood that the detailed description is provided for purposes of illustration and explanation and is not intended to limit the scope of the invention.

It should be noted that although the following description describes the operation and unique advantages of the balance valve of the present invention by taking the application of the balance valve to a luffing hydraulic cylinder control system of an automobile crane as an example, the balance valve of the present invention can be widely applied to a hydraulic control system of a hydraulic actuator (such as a hydraulic cylinder, a hydraulic motor, etc.), which adopts a valve core structure (i.e. the servo actuation valve rod 5 described below) with a unique structure to establish dynamic balance between a hydraulic control signal and a valve core movement position, so that the operation of the hydraulic actuator is more stable and controllable. In addition, referring to fig. 3 and 5 as appropriate, in the following description, the axial effective pressure-receiving area of the relevant hydraulic acting surface is mainly referred to as the force formed by the hydraulic oil acting on the hydraulic acting surface in the axial direction of the servo-actuated valve rod 5 divided by the hydraulic oil pressure, that is, since the specific structure of the hydraulic acting surface may be varied for those skilled in the hydraulic field, for example, the hydraulic acting surface may be formed as a slope, in which case the hydraulic acting force received by the hydraulic acting surface is perpendicular to the inclined hydraulic acting surface, and the hydraulic acting force received by the inclined hydraulic acting surface has a force component in the axial direction of the servo-actuated valve rod 5, which needs to be divided by the hydraulic oil pressure. That is, the effective pressure receiving area in the axial direction of the hydraulically acting surface should be the area of the projection of the hydraulically acting surface on a plane perpendicular to the axial direction of the servo actuator valve rod 5.

The main structure of the balancing valve of the present invention will be described in a hierarchical manner with reference to fig. 2 to 7, and some modifications and related working procedures that are easily conceivable to those skilled in the art will be additionally described in the description, and it should be noted that the valve structure in the hydraulic field may be variously changed, but the present invention is not limited to the detailed structure illustrated below for the specific description as long as it falls within the technical concept of the present invention. Further, on the basis of clearly describing the main structure of the balance valve of the present invention, a hydraulic cylinder control system, a crane, and a dead weight lowering servo control method of the crane to which the present invention is applied will be described. On the basis, in order to facilitate understanding of the originality of the balance valve of the invention, the working process and technical advantages of the balance valve of the invention applied to a control system of a luffing hydraulic cylinder of an automobile crane will be more fully and completely described in detail with reference to a preferred embodiment of fig. 2 to 5.

Referring to fig. 2 to 5, the balance valve according to the basic embodiment of the present invention includes a valve body module 2 formed with a first port a and a second port B; the servo actuating valve rod 5 is slidably accommodated in a hollow cavity of the valve body module 2, and a main spring cavity 6 located at one axial end of the servo actuating valve rod 5 and a first oil cavity 7 and a second oil cavity 8 which are axially distributed at intervals and respectively formed along the circumferential direction of the servo actuating valve rod 5 are separated from the hollow cavity, wherein the first oil cavity 7 is communicated with the first port A, the second oil cavity 8 is communicated with the second port B, and a main spring 3 for applying preset elastic thrust to one axial end of the servo actuating valve rod 5 is arranged in the main spring cavity 6; and a gain adjustment control piston 1c which is accommodated in a piston chamber 12 at the other end in the axial direction of the servo actuator stem 5 and is capable of pushing the servo actuator stem 5 to move toward the main spring chamber 6 under the drive of the pilot oil introduced at the pilot port X of the balance valve to communicate the first oil chamber 7 with the second oil chamber 8; more specifically, the servo actuator stem 5 is formed with a first hydraulic pressure acting surface S1 at an opening/closing flow passage portion S3 corresponding to the first oil chamber 7 and the second oil chamber 8, the first hydraulic pressure acting surface S1 can be gradually exposed to receive an axial hydraulic force acting toward the main spring chamber 6 when the servo actuator stem 5 moves so that the first oil chamber 7 and the second oil chamber 8 communicate with each other, the servo actuator stem 5 is further formed with a second hydraulic pressure acting surface S2, the second hydraulic pressure acting surface S2 is exposed to the second oil chamber 8 or an oil chamber communicating with the second oil chamber 8 so as to be able to receive an axial hydraulic force acting toward the piston chamber 12, and an axial effective pressure receiving area S1a of the first hydraulic pressure acting surface S1 is equal to an axial effective area S2a of the second hydraulic pressure receiving surface S2.

In the balancing valve according to the above-described basic technical solution of the present invention, it can be seen that the balancing valve according to the present invention can realize the basic function of the balancing valve by actuating the valve rod 5 by servo, which mainly adopts a pilot-controlled manner (see more specifically the following description). In general, as is well known to those skilled in the art, a balance valve is typically disposed in a working fluid path of a hydraulic actuator when applied to a hydraulic control system, wherein a first port a is connected to a directional control valve (the directional control valve is typically connected to a fluid inlet path and a fluid return path), and a second port B is connected to the hydraulic actuator (e.g., a rodless chamber of a hydraulic cylinder or a fluid port of a hydraulic motor). When the hydraulic actuating mechanism works in the forward direction (for example, a piston rod of a hydraulic cylinder extends out), the reversing valve is reversed to enable hydraulic oil in the oil inlet oil path to enter from the first port A of the balance valve, and the first port A and the second port B of the balance valve are communicated through the internal oil path of the balance valve through controlling the balance valve (the invention adopts an external hydraulic control mode), so that the oil inlet of the hydraulic actuating mechanism realizes the forward work. When the hydraulic actuator works reversely, the reversing valve is switched to enable the first port A to be communicated with the oil return oil path, and at the moment, the oil return of the hydraulic actuator flows out from the second port B to the first port A through the internal oil path of the balance valve.

The balance valve of the basic technical scheme has the advantages that the original valve core structure and the matched servo hydraulic control structure unit thereof have remarkable improvement on the working stability, the working speed uniformity of the hydraulic actuating mechanism and the control accuracy of the engineering machinery particularly when the hydraulic actuating mechanism works in a reverse direction to return oil. Specifically, when the hydraulic actuator needs reverse oil return, hydraulic oil is introduced through the hydraulic control port X, and the hydraulic control oil drives the gain adjustment control piston 1c to further push the servo actuator valve rod 5 to move to a position where the first oil chamber 7 and the second oil chamber 8 communicate with each other against the elastic urging force of the main spring 3, that is, the first oil chamber 7 and the second oil chamber 8 communicate with each other through the open-close flow passage portion S3. In this case, the balance valve of the present invention establishes a servo dynamic adjustment relationship between the target control signal of the pilot oil pressure X1 and the position of the servo actuator stem 5 (fine range adjustment in a state where the first port a and the second port B are communicated) by adjusting the pilot oil pressure X1 introduced into the pilot chamber 12a from the pilot port X to a target pressure value range, thereby realizing adaptive adjustment of the position of the servo actuator stem 5.

Specifically, first, the pilot oil pressure X1 introduced into the pilot chamber 12a from the pilot port X is adjusted to a target pressure value range, and it should be noted here that, although in the following preferred embodiment of the present invention, the pilot oil pressure X1 in the pilot chamber 12a can be relatively finely adjusted by the servo pilot structure unit 1 integrated in the valve block unit 2 of the present invention, it should be understood that the target pressure value range of the pilot oil pressure X1 can be adjusted by various oil pressure adjusting means in the art, such as an external oil pressure adjusting device (a relief valve, etc.), an external pilot oil adjusting circuit, etc., for those skilled in the art. In this case, the axial hydraulic force received by the booster control piston 1c toward the main spring chamber 6 is X1 × S0, where S0 is the axial effective pressure receiving area of the booster control piston 1c, and further, since the second hydraulic pressure acting surface S2 of the servo actuator valve rod 5 is exposed to the second oil chamber 8 or an oil chamber communicating with the second oil chamber 8, the oil pressure of the second oil chamber 8 is PB, and the second hydraulic pressure acting surface S2 receives the hydraulic force toward the piston chamber 12 is PB × S2a, where S2a is the axial effective pressure receiving area of the second hydraulic pressure acting surface S2. Further, during the movement of the servo actuator valve rod 5 toward the main spring chamber 6, the hydraulic oil flows from the second port B to the open/close port portion S3 at the first port a, i.e., the first hydraulic pressure acting surface S1 (also referred to as an equiaxial acting surface by those skilled in the art) on the servo actuator valve rod 5 is gradually opened, during the gradual opening of the open/close port portion S3, the first hydraulic pressure acting surface S1 is gradually exposed, and at the same time, an equiaxial pressure PB1 (i.e., an oil pressure of the open/close port portion S3) is formed before and after the open/close port portion S3 (similar to the valve port) due to throttling and the like, at this time, the axial hydraulic pressure acting force applied by the first hydraulic pressure acting surface S1 toward the main spring chamber 6 is: PB1 × S1a, where S1a is an axial effective pressure receiving area of the first hydraulically acting surface S1, and S1a and S2a are equal.

Since the servo actuator valve rod 5, which keeps the second port B communicating with the first port a, needs to be maintained within a corresponding position range in the reverse operation state of the hydraulic actuator, in this case, the elastic thrust F of the main spring 3 is an elastic thrust in a state where the main spring 3 is compressed to a state where the first oil chamber 7 and the second oil chamber 8 communicate with each other. The hydraulic balance formula of the servo actuation valve rod 5 can be established according to the pressure difference value formed by the left side and the right side of the servo actuation valve rod 5 as follows:

X1×S0+PB1×S1a＝PB×S2a+F.........(1)

converting equation of formula (1) into equation of formula (2)

X1×S0＝(PB×S2-PB1×S1)+F.........(2)

And (S1a ═ S2a)

X1×S0-F＝S1a×(PB-PB1).........(3)

In the final hydraulic acting force balance formula (3), the difference value of the PB-PB1 pressure determines the flow compensation capability of the servo actuator valve rod 5, and when the reverse working state of the hydraulic actuator fluctuates or the oil return pressure is too large to cause instability (for example, when the amplitude-change angle of the automobile crane amplitude-change hydraulic cylinder is reduced), the difference value of PB-PB1 becomes larger and larger, and the difference value acts on the servo actuator valve rod 5 to push the valve rod to move towards the piston cavity 12, so as to automatically reduce the through-flow opening degree of the opening and closing through-flow port part S3, reduce the flow passing, and establish dynamic slight amplitude adaptive adjustment of the position of the servo actuator valve rod 5. The difference X1 × S0-F determines the control target value of the servo pilot hydraulic pressure, and the signal gain of the pilot pressure target value (i.e., the axial effective pressure receiving area S0 of the gain adjustment control piston 1c) and the difference range PB-PB1 determine whether the servo actuation valve rod 5 has the overcompensation capability and the strength of the overcompensation capability.

Therefore, according to the basic technical scheme of the balance valve, after the pilot-controlled oil pressure target value of X1 × S0-F is determined, the change of the difference value of PB-PB1 between the left and right sides of the servo actuator valve rod 5 caused by the gradual change of the oil pressure PB of the second oil chamber causes the servo actuator valve rod 5 to automatically search and track the balance point to satisfy the formula (3), so that the flow regulation of the opening and closing through-flow port position S3 is self-adaptive to maintain balance, and finally the working speed of the hydraulic actuator is close to the average value, and a dynamic balance state with relatively stable and controllable speed is achieved. Therefore, the balance valve improves the uniformity and controllability of the working speed of the hydraulic actuating mechanism, and establishes the servo relationship between the hydraulic control signal and the position of the valve core, so that the hydraulic actuating mechanism has more stable uniform speed and controllability, and more comfortable and safer operation.

It should be additionally noted that the above formula (3) actually forms a servo feedback control system inside the balance valve, and finally realizes the flow compensation adjustment and even the overcompensation adjustment of the balance valve along with the change of the load. However, it should be noted that the above balance is a dynamic balance, and in practical applications, the pilot oil pressure X1 and the main spring 3 both dynamically change due to a small change in the position of the servo actuator valve rod 5, but this does not affect the realization and establishment of the dynamic balance relationship of the balance valve of the present invention.

On the basis of the above basic technical solution of the balance valve of the present invention, referring to fig. 4, a load feedback oil chamber 9 may be formed on the valve body module 2 along the circumferential direction of the servo actuator valve rod 5, the load feedback oil chamber 9 communicates with the second oil chamber 8 through a load feedback oil passage Ls formed on the valve body module 2, and the second hydraulic acting surface S2 may be exposed to the load feedback oil chamber 9. Of course, the second hydraulic acting surface S2 of the present invention may be formed in various modified structural forms as long as it falls within the technical idea of the present invention, and it is within the scope of the present invention, for example, see fig. 6, in which the second hydraulic acting surface S2 may be directly formed to be exposed to the second oil chamber 8, in which case, without forming the load feedback oil passage Ls, the shape of the second oil chamber 8 may be adjusted accordingly to ensure that the oil pressure of the second oil chamber 8 reaches the second hydraulic acting surface S2.

Referring to fig. 2 and 5, as a preferred embodiment, in order to ensure that the main spring 3 effectively applies elastic thrust to one axial end of the servo actuator valve rod 5, a spring pressing seat 4 may be provided in the main spring chamber 6, the main spring 3 may be installed between the spring pressing seat 4 and the end cover spring seat, and the main spring 3 may apply elastic force to one axial end of the servo actuator valve rod 5 through the spring pressing seat 4. More preferably, the axial center positions of the gain adjustment control piston 1c, the servo actuator valve rod 5 and the spring pressing seat 4 are formed with through

center oil passages

10a,10b,10c, and the respective

center oil passages

10a,10b,10c are engaged with each other when the gain adjustment control piston 1c, the servo actuator valve rod 5 and the spring pressing seat 4 are pressed against each other to form an oil return passage for the hydraulic oil. The advantage of this preferred structure is that, because the main spring chamber of the balance valve is generally connected to the oil return oil passage through the interface or the internal oil passage in the actual use process, the oil return of the hydraulic oil can be effectively realized, and the hydraulic oil is prevented from returning near the gain adjustment control piston 1c to affect the accuracy of the servo adjustment. In addition, the hydraulic control oil generally has less oil quantity, and can effectively lubricate elements in the main spring cavity 6 such as the main spring 3 and the like to a certain extent through the main spring cavity 6, so that the service life is prevented from being influenced by corrosion or other reasons.

Preferably, referring to fig. 5, although the

central oil passages

10a,10b, and 10c have a small diameter, the central oil passage does not affect the pilot oil pressure X1 under normal conditions, so as to affect the servo control, in order to ensure that the pilot servo operation is more stable and reliable, and avoid the pilot oil pressure being affected by the pilot oil return, a partial pressure damping structure 1b may be disposed in the central oil passage 10a of the gain adjustment control piston 1 c. Such a pressure-dividing damping structure may be a damping valve provided in the center oil passage 10a, or may be a hydraulic damping structure directly formed on the inner wall surface of the center oil passage 10 a. The pressure-dividing damping structure 1b can effectively ensure that the oil return speed of the hydraulic control oil is relatively slow, the hydraulic control oil pressure is not influenced due to the fact that the oil return speed of the hydraulic control oil is too fast, meanwhile, the pressure-dividing damping structure can play a stable pressure-stabilizing role in the hydraulic control oil pressure, and the reliability of self-adaptive position adjustment of the servo actuating valve rod 5 is ensured.

Typically, referring to fig. 2, an oil overflow valve 11 may be further integrated in the valve body module 2 of the balance valve of the present invention, wherein an oil inlet of the overflow valve 11 is communicated with the first port a, and an oil outlet of the overflow valve 11 is communicated with the second port B. Because the hydraulic actuator forward during operation, the hydraulic oil of oil feed oil circuit gets into the first port A of balanced valve from the switching-over valve, and because be the working oil circuit, oil mass and oil pressure are all great, in order to prevent that the working oil circuit oil pressure is too big, damage hydraulic control system's hydraulic component, through setting up overflow valve 11 of oil inlet and first port A intercommunication, can control the oil pressure of main working oil circuit effectively, ensure hydraulic system security and reliability.

The valve body module 2 of the balance valve of the invention can comprise a valve block body 2a, and can also be added with related end covers or other valve blocks according to the installation requirements on the basis of the valve block body 2a, for those skilled in the art, the valve body module 2 can be changed in various ways according to the installation requirements, preferably, referring to fig. 5, the valve body module 2 of the balance valve of the invention can comprise a valve block body 2a and a valve sleeve 2b, the valve sleeve 2b is lined in the hollow cavity, because the servo actuation valve rod 5 needs to slide in the hollow cavity in a back and forth sealing manner, the required processing precision is higher, through the arrangement of the valve sleeve 2b, the precision of the internal matching of the balance valve can be ensured, the processing cost can be effectively reduced, and the processing is convenient. In addition, the valve body module 2 may further include an end cover configured according to installation requirements, for example, the valve body module 2 of the balance valve of the present invention may further include a servo control end cover 2c disposed on one side of the valve block body 2a thereof, so as to be used for configuring the servo pilot-operated structural unit 1 of the balance valve of the present invention, for example, the above-mentioned piston cavity 12, pilot-operated port X, and compensation capability control valve 1d described below may be disposed on the servo control end cover 2 c. The valve body module 2 has various structural modes, and the valve body module 2 is generally arranged into a split structure, so that the valve body module is more convenient to mount, adjust, process and the like.

Referring to fig. 2 to 5, in particular, the gain adjustment control piston 1c divides the piston cavity 12 into a hydraulic control cavity 12a and a movable cavity 12B, and the other axial end of the servo actuator valve rod 5 extends into the movable cavity 12B, so that when the gain adjustment control piston 1c is driven by the hydraulic control oil, it can effectively contact with the other axial end of the servo actuator valve rod 5 and apply a thrust to the servo actuator valve rod 5 to push the servo actuator valve rod 5 to move towards the main spring cavity 6, thereby ensuring that the servo actuator valve rod 5 can move in place to enable the first port a and the second port B to communicate with each other. In addition, the hydraulic control port X is communicated with the hydraulic control chamber 12a so as to introduce hydraulic control oil into the hydraulic control chamber 12a, the general hydraulic control port X is used for connecting an external hydraulic control oil path, the external hydraulic control oil path conveys the hydraulic control oil to the hydraulic control port X according to the operation of an engineering machinery operator, and the external hydraulic control oil path can be a simple oil path connected to a working oil path of the hydraulic execution mechanism or a special hydraulic control oil path provided with an oil pressure adjusting device according to application requirements.

Preferably, as an optimized implementation form of the servo hydraulic control structure unit 1 of the present invention, an oil inlet damping structure 1a may be disposed on a communication oil passage between the hydraulic control port X and the hydraulic control chamber 12a, and similar to the above-mentioned partial pressure damping structure, the oil inlet damping structure may be a damping valve disposed on the communication oil passage, or may be a hydraulic damping structure directly formed on the communication oil passage. As the component element of the servo hydraulic control structure unit in an optimized form, the oil inlet damping structure 1a can play a role in combing, filtering and stabilizing hydraulic pressure for the input of hydraulic control oil, so that the resolution (namely precision) of the hydraulic control oil pressure X1 is more accurate, and the adjustment of the hydraulic control oil pressure X1 is more convenient. In addition, the partial pressure damping structure 1b mentioned above can also exert a smooth hydraulic action on the pilot oil pressure by the function of the relief damping filter, which can also exert an improved effect on the accuracy of the pilot oil pressure X1.

As a more preferable technical solution, referring to fig. 3 and 5, the balance valve of the present invention may further include a compensation capability control valve 13 provided on the valve body module 2, the compensation capacity control valve 13 comprises a compensation control piston 13b which can be arranged in a compensation piston cavity in a sliding mode, the compensation control piston 13b divides the compensation piston cavity into a hydraulic action cavity 13a and a compensation spring cavity 13c, the hydraulic action cavity 13a is communicated with a hydraulic control cavity 12a, a compensation control spring 13g which can adjust elastic force is arranged in the compensation spring cavity 13c, the compensation control spring 13g is preset to exert elastic force on the compensation control piston 13b, a stop flange 13i is arranged on the outer periphery of the compensation control piston 13b, a circumferential step 13h is arranged on the inner circumferential surface of the compensation piston cavity, and the stop flange 13i and the circumferential step 13h can stop mutually to limit the movement stroke of the compensation control piston 13b when the compensation control piston 13b moves to a certain position. The compensation-capacity control valve 13 is similar to an oleo-elastic regulator, in that the compensation control piston 13b has a relatively small preset stroke in the compensation piston chamber, the compensation commanding piston 13b can compress the compensation commanding spring 13g in this stroke, and by adjusting the preset elastic force of the compensation commanding spring 13g (adjusted by the spring adjusting cap 13 m), the pilot oil pressure of the hydraulic apply chamber 13a communicating with the hydraulic apply chamber 12a can be made to vary within a preset target range, which makes the adjustment of the pilot oil pressure X1 relatively easy, that is, as long as the compensation pilot piston 13b of the compensation capability control valve 13 is not pushed to the end of the movement stroke by the pilot oil (the stop flange 13i and the circumferential step 13b stop against each other), it can be considered that the pilot oil pressure X1 is within the effective balance target range and belongs to the effective pilot oil pressure target control value.

Further preferably, referring to fig. 5, an axial central oil passage 13e may be formed in the compensation control piston 13b, the compensation control spring 13g is sleeved on the spring pushing seat 13l and applies an elastic pushing force to the end surface of the compensation control piston 13b through a branch end of the spring pushing seat 13l, and a sealing ball 13f for sealing a port of the axial central oil passage 13e is disposed between a branch port of the branch end and the end surface of the compensation control piston 13 b. The advantage of this structure is that, as described above, since the balance valve of the present invention uses the single servo-actuated valve rod 5 as the valve core, the basic function of the balance valve is realized, even during the dynamic adjustment of the compensation balance, the pilot oil pressure X1 will exceed the adjustment range of the compensation capacity control valve 13 when necessary, i.e. the compensation control piston 13b will be pushed to the end of the movement stroke by the pilot oil, in this case, the oil pressure adjustment function of the compensation capacity control valve 13 fails, i.e. the compensation capacity control valve 13 limits the range of the target control signal of the pilot oil pressure X1, and the setting adjustment pressure range of the compensation capacity control valve 13 is required to be proper to ensure the validity of the target control signal of the pilot oil pressure X1. In the event of failure of the compensation capacity control valve 13, since the compensation capacity control valve 13 belongs to a relatively delicate hydraulic component, in order to avoid the pilot oil pressure X1 being too large, and the compensating capacity control valve 13 being damaged by that time, the pilot oil can push the sealing ball 13f to continue to compress the compensating control spring 13g via the axial center oil passage 13e in this preferred form of construction, thereby leading the hydraulic control oil to reach the compensation spring cavity 13c, leading the hydraulic control oil pressure to exert hydraulic acting force on the spring cavity end of the compensation control piston 13b, offsetting the acting force of the hydraulic control oil in the hydraulic acting cavity 13a on one end of the hydraulic acting cavity of the compensation control piston 13b to a certain extent, therefore, the extrusion of the stop flange 13i and the circumferential step 13b and the compensation control piston 13b to the cover body of the servo control end cover 2c is reduced, the damage of the internal elements of the compensation capacity control valve 13 is prevented, and the working reliability and the service life of the system are improved.

Furthermore, referring to fig. 5, the inner diameter of the section of the compensation piston chamber provided with the circumferential step 13h is generally larger than the hydraulic acting chamber 13a and the compensation spring chamber 13c, thereby forming a flange portion movement chamber 13k of the stopper flange 13i, which flange portion movement chamber 13k can communicate with the movable chamber 12b through an oil drain channel 13j, in order to avoid accumulation of collected hydraulic oil in the flange portion movement chamber 13k, which leads to reduction of the oil pressure regulation accuracy of the compensation capacity control valve 13, and during use of the balance valve of the present invention, the movable chamber 12b generally needs to be connected to an oil return channel through an external oil channel or an interface.

The basic technical scheme and various preferable technical schemes of the balance valve are described above, on the basis, the invention also provides a hydraulic cylinder control system, and the oil circuit connection of the hydraulic cylinder control system is common to those skilled in the art, so that the oil circuit connection is not shown in the attached drawings. Specifically, the hydraulic cylinder control system of the present invention includes a hydraulic cylinder, a rod chamber of the hydraulic cylinder is connected to two working ports of a reversing valve (for example, a three-position four-way reversing valve) via a first working oil path, and a rodless chamber of the hydraulic cylinder is connected to two working ports of the reversing valve via a second working oil path, an oil inlet port and an oil return port of the reversing valve are connected to the oil inlet path and the oil return path, wherein a balance valve is disposed on the second working oil path connected to the rodless chamber, the balance valve may be a balance valve according to any one of the above technical solutions of the present invention, a first port a of the balance valve is connected to the reversing valve, a second port B of the balance valve is connected to the rodless chamber of the hydraulic cylinder (that is, an oil balance valve is disposed on the second working oil path, one end of the second working oil path is connected to the rodless chamber.

In addition, the invention further provides a crane, and the luffing hydraulic cylinder control system of the crane adopts the hydraulic cylinder control system. The hydraulic cylinder control system of the crane adopts the hydraulic cylinder control system with the balance valve, and forms a unique control method during the self-weight lowering operation (namely, inverted amplitude changing operation), and the control method specifically comprises the following steps as shown in figure 7:

first, the pilot oil is introduced through the pilot port X to drive the gain adjustment control piston 1c to push the servo actuator valve rod 5 to move, so that the first oil chamber 7 and the second oil chamber 8 communicate with each other and the first hydraulic pressure acting surface S1 is gradually exposed to receive the hydraulic pressure acting force;

secondly, the hydraulic control oil pressure in the control hydraulic control cavity is in the target control oil pressure range, so that the servo actuating valve rod 5 performs self-adaptive dynamic position adjustment according to the following formula:

X1×S0-F＝S1a×(PB-PB1)；

as described above, X1 is the pilot oil pressure in the pilot chamber, S0 is the axial effective pressure receiving area of the gain control piston 1c, F is the elastic thrust of the main spring 3 compressed in the state where the first oil chamber 7 and the second oil chamber 8 are communicated with each other, and it also changes with a small adjustment of the position of the servo actuator stem 5, S1a is the axial effective pressure receiving area of the first hydraulic acting surface S1, PB is the oil pressure in the second oil chamber 8, and PB1 is the oil pressure of the opening/closing flow passage portion S3 where the first oil chamber 7 and the second oil chamber 8 are communicated with each other.

As described above, alternatively, the pilot oil pressure in the pilot chamber may be controlled to be in the target pilot oil pressure range by the external oil pressure adjusting device; or the pilot oil pressure in the pilot chamber is controlled to be in the target pilot oil pressure range by the above-described compensatory ability control valve 13 provided in the balance valve.

The basic technical solutions and various preferred embodiments of the balancing valve, the hydraulic cylinder control system, the crane according to the present invention have been described above in a hierarchical manner, wherein the specific technical effects of the derricking operation of the crane are not explained in detail when the hydraulic control system according to the present invention is applied to the crane, the basic functions and technical advantages of the balancing valve according to the present invention when applied to the derricking hydraulic cylinder system of the crane will be described relatively completely with reference to the balancing valve according to the preferred embodiment of fig. 2 to 5, so that the technical originality of the present invention can be understood more deeply. Since the main structure of the balancing valve of fig. 2 to 5 and its associated simple modified structure have been described above, they will not be described again.

Referring to fig. 2 to 5, when the balance valve is applied to a luffing hydraulic cylinder control system of a crane, firstly, when the crane is in luffing operation, hydraulic oil in an oil inlet path enters a first port a of the balance valve through a reversing valve, in this case, the balance valve of the present invention introduces hydraulic oil through a hydraulic control port X, in the forward operation, the hydraulic control oil with larger oil pressure can be introduced into the hydraulic control port X, so that the compensation capacity control valve 13 fails, the servo actuator valve rod 5 is relatively and quickly moved to the valve rod position where the first oil chamber 7 and the second oil chamber 8 are communicated with each other by fast switching, the oil inlet oil path enters the hydraulic oil of the inverted first port A and is conveyed to the rodless cavity of the inverted variable amplitude hydraulic cylinder through the first oil chamber 7, the opening and closing through-flow port part S3, the second oil chamber 8 and the second port B, and therefore the piston rod of the variable amplitude hydraulic cylinder extends out, and the forward variable amplitude operation is formed.

When the forward amplitude-variable operation of the crane is in place and the crane boom is kept at a certain position, the hydraulic control oil in the hydraulic control cavity is decompressed, so that the servo actuating valve rod 5 returns to the position where the first oil cavity 7 and the second oil cavity 8 are cut off from each other under the action of the elastic thrust of the main spring 3, the hydraulic oil in the rodless cavity of the amplitude-variable hydraulic cylinder cannot return oil through the second oil cavity 8, and the crane boom is locked at a required position.

When the jib of the crane is reversely amplitude-variable operated, the rodless cavity of the amplitude-variable hydraulic cylinder can return oil by generally pressing a piston rod of the amplitude-variable hydraulic cylinder by the self weight of the jib of the crane, but the jib of the crane has heavier weight, and in the reverse amplitude-variable operation, the safety, speed uniformity and controllability of the reverse amplitude-variable operation need to be ensured by the self weight of the jib of the crane. Specifically, as shown in fig. 5, when the crane reverses its amplitude, the hydraulic control end X enters hydraulic control oil, and after the hydraulic control oil is adjusted by the oil inlet damping structure 1a and the partial pressure damping structure 1b (the initial hydraulic control oil pressure X1 may be larger, so as to facilitate the quick switching of the balance valve), the hydraulic control oil pressure X1 acts on the gain adjustment piston 1c, and moves rightward through the gain adjustment piston 1c to push the servo actuation valve rod 5 to move rightward together, and simultaneously resists the elastic thrust F formed by the compression of the main spring 3.

The oil pressure PB in the second oil chamber 8 (i.e., the load feedback pressure in the rodless chamber of the luffing hydraulic cylinder) is transmitted to the second hydraulic pressure action surface S2 through the load feedback oil passage LS, acts on the right end of the servo actuator valve rod 5, during the rightward movement of the servo actuator valve rod 5, the first hydraulic acting surface S1 (i.e. the equiaxed hydraulic acting surface referred to by those skilled in the art) on the servo actuator valve rod 5 where the oil flows to the first port a is gradually opened, the oil pressure PB1 (i.e., the equiaxed pressure) of the opening-closing port portion at which the first oil chamber and the second oil chamber formed before and after the opening-closing port portion S3 (similar to the through-flow valve port) communicate with each other is generated in the process of gradually opening the first hydraulic working surface S1, where S1a is the axial effective pressure receiving area of the first hydraulic pressure acting surface S1, and S1a and the axial effective pressure receiving area S2a of the second hydraulic pressure acting surface S2 are equal.

Because the second port B and the first port a are kept communicated with the servo actuation valve rod 5 in the inverted amplitude operation working state of the crane, the servo actuation valve rod 5 needs to be maintained within a corresponding position range, in this case, a hydraulic balance formula of the servo actuation valve rod 5 can be established according to a pressure difference value formed by the left side and the right side of the servo actuation valve rod 5 as follows:

X1×S0+PB1×S1a＝PB×S2a+F.........(1)

converting equation of formula (1) into equation of formula (2)

X1×S0＝(PB×S2-PB1×S1)+F.........(2)

And (S1a ═ S2a)

X1×S0-F＝S1a×(PB-PB1).........(3)

In the final hydraulic acting force balance formula (3), the difference value of the PB-PB1 pressure determines the flow compensation capability of the servo actuating valve rod 5, and as the amplitude-reversing operation of the amplitude-reversing hydraulic cylinder is performed, when the amplitude-reversing angle of the crane amplitude-reversing hydraulic cylinder is reduced, the difference value of PB-PB1 becomes larger and larger, and the difference value acts on the servo actuating valve rod 5 to push the valve rod to move towards the piston cavity 12, so as to automatically reduce the through-flow opening degree of the opening and closing through-flow opening part S3, reduce the flow passing, and establish the dynamic micro-amplitude adaptive adjustment of the position of the servo actuating valve rod 5. The difference X1 × S0-F determines the control target value of the servo pilot hydraulic pressure, and the signal gain of the pilot pressure target value (i.e., the axial effective pressure receiving area S0 of the gain adjustment control piston 1c) and the difference range PB-PB1 determine whether the servo actuation valve rod 5 has the overcompensation capability and the strength of the overcompensation capability. After the difference value of X1 multiplied by S0-F is determined, the PB-PB1 difference value change caused by the gradual change of the PB pressure on the left and the right of the servo actuating valve rod 5 can cause the servo actuating valve rod 5 to automatically search and track a balance point to meet the formula (3), so that the flow through the opening and closing flow passage port part S3 is self-adaptively balanced, the lowering speed of the inverted amplitude of the crane is finally caused to tend to be an average value, and the speed controllable state is achieved.

In summary, the present invention has the following advantages compared with the prior art:

the balance valve adopts an original valve core structure and a matched servo hydraulic control structure unit, and particularly has the technical effects of obviously improving the working stability, the working speed uniformity of the hydraulic actuating mechanism and the control accuracy of engineering machinery when the hydraulic actuating mechanism works in a reverse direction for oil return. When the hydraulic actuator needs to return oil reversely, hydraulic oil is introduced through the hydraulic control port X, and the hydraulic control oil drives the gain adjustment control piston 1c to further push the servo actuator valve rod 5 to move to a position where the first oil chamber 7 and the second oil chamber 8 communicate with each other against the elastic thrust of the main spring 3, that is, the first oil chamber 7 and the second oil chamber 8 communicate with each other through the opening and closing flow passage portion S3. In this case, the balance valve according to the present invention adjusts the range of the pilot oil pressure X1 introduced into the pilot chamber 12a through the pilot port X to the target pressure value, and establishes the servo dynamic adjustment relationship between the target control signal of the pilot oil pressure X1 and the position of the servo actuator stem 5 (fine range adjustment in the state where the first port a and the second port B are communicated), thereby realizing the self-adaptive adjustment of the position of the servo actuator stem 5. Specifically, after the target value of the pilot oil pressure of X1 × S0-F is determined, the change of the difference value of PB-PB1 between the left and right sides of the servo actuator valve rod 5 due to the gradual change of the oil pressure PB of the second oil chamber causes the servo actuator valve rod 5 to automatically find and track the balance point to satisfy the formula (3), so that the flow rate adjustment of the opening and closing flow passage part S3 is used for self-adaptation to maintain balance, and finally the working speed of the hydraulic actuator is close to the average value, and a dynamic balance state with relatively stable and controllable speed is achieved. Therefore, the balance valve improves the uniformity and controllability of the working speed of the hydraulic actuating mechanism, and establishes the servo relationship between the hydraulic control signal and the position of the valve core, so that the hydraulic actuating mechanism has more stable uniform speed and controllability, and more comfortable and safer operation.

In particular, in the preferred embodiment of the present invention, the servo hydraulic control structure unit 1 of the balance valve of the present invention adopts a control method with a compensation capability control valve function, and simultaneously, in cooperation with an oil path type with improved resolution, transmits a hydraulic control oil pressure target value to the servo action valve rod 5, and the servo action valve rod automatically follows to meet the target value, and the target control signal hydraulic control oil pressure X1 can be continuously changed, thereby realizing the requirements of each section. The control signal and the load feedback signal form continuous adjustment to determine the servo adjustment of the position of the servo actuating valve rod 5, and finally the speed of the hydraulic actuating mechanism tends to be stable, for example, the problems of too slow large angle and too fast small angle of the amplitude reduction of the crane are solved, and the uniformity and the controllability are obviously improved.

The preferred embodiments of the present invention have been described in detail with reference to the accompanying drawings, however, the present invention is not limited to the specific details of the above embodiments, and various simple modifications can be made to the technical solution of the present invention within the technical idea of the present invention, and these simple modifications are within the protective scope of the present invention. It should be noted that the various features described in the above embodiments may be combined in any suitable manner without departing from the scope of the invention. The invention is not described in detail in order to avoid unnecessary repetition.

In addition, any combination of the various embodiments of the present invention is also possible, and the same should be considered as the disclosure of the present invention as long as it does not depart from the spirit of the present invention.

Claims

1. A balance valve comprising a valve body module (2) formed with a first port (a) and a second port (B), wherein the balance valve further comprises:

the valve body module comprises a servo actuating valve rod (5), a main spring cavity (6) and a first oil cavity (7) and a second oil cavity (8), wherein the main spring cavity is slidably accommodated in a hollow cavity of the valve body module (2) and is separated from the hollow cavity into the main spring cavity, the main spring cavity is located at one axial end of the servo actuating valve rod (5), the first oil cavity (7) and the second oil cavity are axially distributed at intervals and are respectively formed along the circumferential direction of the servo actuating valve rod (5), the first oil cavity (7) is communicated with a first port (A), the second oil cavity (8) is communicated with a second port (B), and a main spring (3) used for applying preset elastic thrust to one axial end of the servo actuating valve rod (5) is arranged in the main spring cavity (6); and a gain adjustment control piston (1c) which is accommodated in a piston chamber (12) at the other axial end of the servo actuator stem (5) and is capable of pushing the servo actuator stem (5) toward the main spring chamber (6) under the drive of a pilot oil introduced at a pilot port (X) of the balance valve to communicate the first oil chamber (7) with the second oil chamber (8);

wherein the servo actuator valve rod (5) is provided with a first hydraulic acting surface (S1) at an opening and closing flow passage part (S3) corresponding to the first oil chamber (7) and the second oil chamber (8), and the first hydraulic acting surface (S1) can be gradually exposed to bear the axial hydraulic acting force towards the main spring chamber (6) in the process that the servo actuator valve rod (5) moves to enable the first oil chamber (7) to be communicated with the second oil chamber (8); and the servo actuator valve rod (5) is further provided with a second hydraulic acting surface (S2), the second hydraulic acting surface (S2) is exposed to the second oil chamber (8) or an oil chamber communicated with the second oil chamber so as to be capable of bearing axial hydraulic acting force towards the piston chamber (12), and the axial effective pressure receiving area (S1a) of the first hydraulic acting surface (S1) is equal to the axial effective pressure receiving area (S2a) of the second hydraulic acting surface (S2).

2. The balanced valve according to claim 1, wherein a load feedback oil chamber (9) is further formed on the valve body module (2) along the circumferential direction of the servo actuator valve stem (5), the load feedback oil chamber (9) communicates with the second oil chamber (8) through a load feedback oil passage (Ls) formed on the valve body module (2), and the second hydraulic-pressure acting surface (S2) is exposed to the load feedback oil chamber (9).

3. A balancing valve according to claim 1, wherein the main spring chamber (6) is provided with a spring biasing seat (4), the main spring (3) being mounted between the spring biasing seat (4) and an end cap spring seat, the main spring (3) exerting a resilient force on the axial end of the servo actuator valve stem (5) via the spring biasing seat (4).

4. A balance valve according to claim 3, wherein the gain adjustment control piston (1c), the servo actuator stem (5) and the spring biasing seat (4) are formed with through center oil passages (10a,10b,10c) at axial center positions thereof, and each of the center oil passages (10a,10b,10c) is engaged with each other to form an oil return passage for the hydraulic oil when the gain adjustment control piston (1c), the servo actuator stem (5) and the spring biasing seat (4) are biased against each other.

5. The balance valve according to claim 1, wherein a partial pressure damping structure (1b) is provided in the center oil passage (10a) of the gain adjustment control piston (1 c).

6. The balancing valve according to claim 1, wherein a relief valve (11) is integrated in the valve body module (2), the relief valve (11) having an oil inlet communicating with the first port (a) and an oil outlet communicating with the second port (B).

7. The balancing valve according to claim 1, wherein the valve body module (2) comprises a valve block body (2a) and a valve sleeve (2b), the valve sleeve (2b) lining the hollow cavity.

8. A balancing valve according to any of claims 1 to 7, wherein the gain adjustment control piston (1c) divides the piston chamber (12) into a hydraulic control chamber (12a) and a movable chamber (12b), the axially other end of the servo actuator valve stem (5) protruding into the movable chamber (12b), the hydraulic control port (X) communicating with the hydraulic control chamber (12 a).

9. The balance valve according to claim 8, wherein an oil inlet damping structure (1a) is provided on a communication oil passage between the hydraulic control port (X) and the hydraulic control chamber (12 a).

10. The balancing valve according to claim 8, wherein the balancing valve further comprises a compensation capability control valve (13) provided on the valve body module (2), the compensation capability control valve (13) comprising a compensation control piston (13b) slidably provided in a compensation piston cavity, the compensation control piston (13b) dividing the compensation piston cavity into a hydraulic action cavity (13a) and a compensation spring cavity (13c), the hydraulic action cavity (13a) communicating with the hydraulic control cavity (12a), a compensation control spring (13g) capable of adjusting an elastic force provided in the compensation spring cavity (13c), the compensation control spring (13g) being preset to apply an elastic force to the compensation control piston (13b), a stopper flange (13i) provided on an outer periphery of the compensation control piston (13b), and a circumferential step (13h) provided on an inner peripheral surface of the compensation piston cavity, the stop flange (13i) and the circumferential step (13h) can stop each other when the compensation control piston (13b) moves to the position so as to limit the movement stroke of the compensation control piston (13 b).

11. The balance valve according to claim 10, wherein an axial central oil passage (13e) is formed in the compensation control piston (13b), the compensation control spring (13g) is sleeved on a spring pushing seat (13l) and applies elastic pushing force to an end face of the compensation control piston (13b) through a branch end of the spring pushing seat (13l), and a sealing ball (13f) for sealing a port of the axial central oil passage (13e) is arranged between a fork opening of the branch end and the end face of the compensation control piston (13 b).

12. The balancing valve according to claim 10, wherein the section of the compensation piston chamber provided with the circumferential step (13h) has a larger inner diameter than the hydraulically acting chamber (13a) and the compensation spring chamber (13c), forming a flange portion movement chamber (13k) of the stop flange (13i), which flange portion movement chamber (13k) communicates with the movable chamber (12b) through an oil drain (13 j).

13. The balancing valve according to claim 10, wherein the valve body module (2) comprises a servo control end cap (2c) provided at one side of its valve block body (2a), the piston chamber (12), the pilot control port (X) and the compensation capacity control valve (1d) being provided at the servo control end cap (2 c).

14. A hydraulic cylinder control system comprising a hydraulic cylinder, wherein a rod chamber of the hydraulic cylinder is connected to a directional valve via a first working oil path and a rodless chamber of the hydraulic cylinder via a second working oil path, the directional valve is connected to an oil inlet path and an oil return path, and a balance valve is disposed on the second working oil path, wherein the balance valve is the balance valve according to any one of claims 1 to 13, the first port (a) of the balance valve is connected to the directional valve, the second port (B) of the balance valve is connected to the rodless chamber of the hydraulic cylinder, and the hydraulic control port (X) is connected to the hydraulic control oil path.

15. A crane comprising a luffing hydraulic cylinder control system, wherein the luffing hydraulic cylinder control system is a hydraulic cylinder control system according to claim 14.

16. A crane dead weight lowering servo control method, wherein the crane is a crane according to claim 15, the method comprising the steps of:

firstly, introducing hydraulic oil through the hydraulic control port (X) to drive the gain adjustment control piston (1c) to push the servo actuator valve rod (5) to move, so that the first oil chamber (7) and the second oil chamber (8) are communicated with each other and the first hydraulic action surface (S1) is gradually exposed to bear hydraulic action force;

secondly, the hydraulic control oil pressure in the hydraulic control cavity is controlled to be in a target control oil pressure range, so that the servo actuating valve rod (5) carries out self-adaptive dynamic position adjustment according to the following formula:

X1×S0-F＝S1a×(PB-PB1)；

wherein X1 does the liquid accuse oil pressure in the liquid accuse intracavity, and S0 does the effective pressurized area in the axial of gain adjustment control piston (1c), and F does main spring (3) are compressed to first oil pocket (7) with the elastic thrust under the mutual intercommunication state of second oil pocket (8), and S1a is the effective pressurized area in the axial of first hydraulic pressure working face (S1), and PB is the oil pressure in second oil pocket (8), and PB1 is the oil pressure of the switching through-flow mouth position (S3) that first oil pocket (7) and second oil pocket (8) communicate each other.

17. A crane dead weight lowering servo control method, wherein, in the second step,

controlling the hydraulic control oil pressure in the hydraulic control cavity to be in a target control oil pressure range through an external oil pressure adjusting device; or

And controlling the hydraulic control oil pressure in the hydraulic control cavity to be in a target control oil pressure range through a compensation capacity control valve (13) arranged in the balance valve.